An Unmanned Aerial Vehicle (UAV), commonly referred to as a drone, is an aircraft without a human pilot. It is controlled either by remote control using a radio signal, or, autonomously using an onboard computer system. UAVs are commonly used in military operations where missions are often too hazardous to deploy manned aircraft.
The use of personal drones has become increasingly popular over the last few years. Manufacturers have developed a wide variety of multicopters with three or more rotary propellers that are used for lift and propulsion, with the most popular version being a four rotor quadcopter. Advances in microelectromechancial system (MEMS) gyroscopes and accelerometers have allowed onboard computers to autonomously sense and control the pitch, roll, and yaw of these rotary multicopters. Some advanced personal drones are also equipped with global positioning systems (GPS) and compass microcircuits that allow the onboard computer to fly autonomously between preprogrammed waypoints. These systems also allow the multicopters to return safely to a home position given a low battery or lost telemetry signal situation. Multicopters are often equipped with a camera system for aerial photography. The main advantage of a multicopter its flight maneuverability including vertical takeoffs, landings, and the ability to hover in a fixed position. The main limitation of a multicopter is its limited flight time due to battery charge limitations. The typical flight time for a personal multicopter drone is 5-15 minutes.
Another common type of personal drone is a rotary propeller powered fixed wing plane. Fixed wing planes typically cost more than multicopters because they require servos and linkages to actuate flight control surfaces such as ailerons, a rudder, and an elevator. Fixed wing drones can be equipped with all of the sensors and onboard computers used by multicopters for autonomous flight. The main advantage of fixed wing planes is their longer flight time, typically 30-60 minutes on a battery charge. Flight time is extended because the wings provide lift. The main disadvantage of fixed wing planes is their limited flight maneuverability. Because they require a forward thrust to provide lift, they cannot perform vertical takeoffs and landings, and they cannot hover in a fixed position in space.
There are personal drones that integrate a multicopter platform with a fixed wing aircraft design. These personal drones typically use four propeller drives oriented in the vertical position for vertical takeoff capability. Once at cruising attitude, motorized mechanisms rotate the propeller drives towards the horizontal position and the aircraft functions as a fixed wing plane. These hybrid drones are costly because they require additional motors and linkages to tilt multiple propeller drives. These drones are often quite large because of their fixed wingspans, making them difficult to store and transport.